> > from. The wording in GPLv2 is: > > > > If you cannot distribute so as to satisfy simultaneously your > > obligations under this License and any other pertinent obligations, > > then as a consequence you may not distribute the Program at all. > > For example, if a patent license would not permit royalty-free > > redistribution of the Program by all those who receive copies > > directly or indirectly through you, then the only way you could > > satisfy both it and this License would be to refrain entirely from > > distribution of the Program. > > This means if you try to enforce royalties on a patent in a piece of > GPLv2 software, you and everyone else lose the right to distribute it. > However, to enforce or license royalty free is an existing choice. The > damage caused by making the programme undistributable is assessable > against the value of the patent.

I think you would have a hard time convincing a judge that "permitroyalty-free redistribution by all those who receive copies directlyor indirectly through you" applies only to "right now", and you canreserve the right to start charging royalties or other enforcements ata later date.

It doesn't say "right now" or "temporarily". It also talks aboutpeople who receive it indirectly through you, and doesn't qualify thatwith "as long as they check back with you that you still think itsOK".

If a company decided down the track to 'monetise' one of theirpatents, and begun by stopping distribution of the GPLv2 program, thenI suspect that the copyright holders of that program could take actionagainst them for having been in breach of the license for the periodof distribution. What the penalty for that might be is hard to tell(it might depend on the jurisdiction and whether the copyright isregistered with the LOC in places like the US). I could certainlyimagine circumstances where the penalty is quite substantial.